| 研究実績の概要 |
In this project, we discovered that chronic extra-terrestrial solar day (non-24-h) light-dark condition reorganizes the network of circadian clocks in the suprachiasmatic nucleus (SCN). The reorganization patterns are analogous to those under seasonal light-dark conditions. We created a computational tool for analyzing the reorganization (Moran's I) and a simple model that describes the network dynamics. Through collaborations with Switzerland and USA, we reported our experimental finding in Neuron (2017), which showed that tunable GABA excitability is responsible for this reorganization and region-specific changes at the epigenetic level underlie the tunability. We then moved our focus to analysis and mathematical modeling of the data. The SCN network can be seen as a generator of spatial patterns. We developed a new quantitative measure for spatiotemporal patterns in the SCN and published in Bioinformatics (2017), with collaborators in Germany. We also worked out the detailed mathematics of the network dynamics in the SCN in relation to the external light environment, published in European Journal of Neuroscience through collaboration with USA. To understand how this reorganization influences the overall in vivo dynamics, we extended our study beyond the SCN to accessory circadian clocks in the brain. We found compelling evidence that internal disorganization of circadian clocks between the SCN and the choroid plexus directly affects behavioral rhythms. This work is currently under revision at Nature Communications and is a result of collaborations with Germany and USA.
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